Job planning device



March 11, 1941. R c, HANFORD Jos PLANNING DEVICE' 2 Sheets-'Sheet 1Filed Aug. 1o, 1959 ATTORNEYS March 11, 1941. R, Q HANFORD 2,234,248

JOB PLANNING DEVICE Filed Aug. 10, 1939 2 Sheets-Shea?. 2

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P r /C76- 5 BY H Mono C #4h/Fae@ l/Md SQ/W/mf ATTORNEY Patented Mar. 11,1941 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to improvements in job planning devices andparticularly to means for facilitating the planning of work inaccordance with available man-hours and other require- I5 ments.

In a manufacturing plant, for example, where various products are beingmanufactured, there are commonly a considerable* number of units ofproduction, which may be called lots, `in

l process at the same time. `Such lots may differ widely in the totalamount of Work they require, the interval of time over which they arerequired or desired to be spread, and the amount of work which canprofitably be spent on them 15 at various stages of their progressthrough the plant. It is also a matter of common experience that theproportion of the total operating facilities which is available forapplication to a particular lot varies depending upon the presence '-0of other work in the plant. Insuflicient regard for or knowledge ofthese variable factors frequently results in wasteful stock chasing,unnecessarily large in-process inventory, uncertaint ty as to shippingdates, delay of the completion 5 of work, and general inefficiency.

The principal object of this invention is to provide means for planningwork in an orderly manner whereby the above variable factors may Y betaken into account and emcient and econom- 3" ical production may beaccomplished.

According to the invention, the work of a lot is broken down intoclasses and subclasses of Work according to a definite procedure, andthese classes and subclasses are empirically arranged 3 with respect toeach other and with respect to time so that the work may be done indesired order and with due regard to the variable factors above referredto.

In the accompanying drawings 40 Figs. 1 and 2 are plan and elevationalviews respectively of one form of device which may be used in carryingout the invention, the movable elements being arranged in a particularmanner; Fig. 3 is a table representing a break-down of 45 the work of ahypothetical lot; and

Figs. 4 and 5 are diagrams illustrating two different arrangements ofthe work of the table in Fig. 3.

Referring to the drawings, II is a support of 5" any suitable material,for example, Wood, heavy cardboard, or the like. The surface of thissup- Vport is divided into areas of uniform width by lines I2. Aplurality of strips I3a, I3b, etc., formed of cardboard or othersuitable material 50 adapted to bear a column of figures, are removablysecured to the surface of the support Il by thumbtacks Il or by anyother suitable means such as Scotch tape, temporary adhesive, or thelike. Upon each of these cards is arranged a column of characters I5,both their number and 5 their numerical significance constitutingfactors tending to identify the work to be performed and being, inaddition, an indication of the quantity of work involved. Thesecharacters are arranged with spacing corresponding to the spacing of thelines I2 so that when a. card is placed in such a position on thesupport that one character falls within the area between adjacent lineseach of the other characters will likewise fall within a different oneof these areas.

To facilitate the identification of characters lying within the samearea but on different cards, I provide a member I 6 movable over thesurface of the support and having a straight edge I1. This member issecured by screws I8 and shoul- 20 dered studs I9 to a cable 20 whichpasses over pulleys 2I secured to the corner portion of the support, allin the usual manner of constructing a straight edge member movableparallel to itself, as in a drafting machine or the like.

The mode of operation of the invention will now be further described byWay of example as applied to the planning of the production of alotconsisting of the parts required for a group of identical machines.lowing assumptions are made, all of which are in accord with conditionsfrequently encountered in practice:

(a) The lot consists of 1085 parts of which 100 require 12 operations,60 require 11 opera- 35 tions, etc., as indicated in Fig. 3.

(b) The operations on each part are to be performed consecutively and aperiod of two working d-ays is to be allowed in which to perform each ofthe successive operations on the parts of a given group.

(c) 'I'he work required to perform each operation is on the average 1.5man-hours.

(d) The plant cannot spend more than 550 man-hours per day on any onelot.

(e) The man-hours available for this lot over and above those reservedfor other work in process are as shown in column 25 marked "I-IrS.

available (Fig. 1).

(f) The work of the lot is Vto start gradually, reach a maximum, anddecrease gradually with lapse of time.

(y) Work on the lot may not be started before June lst and must befinished by July 27th.

In applying the invention to this example, the

In this example, the fol- 30 work is divided into classes consisting ofparts requiring the same number of operations. and each class isassociated with one of the cards I3. These classes are divided intosubclasses consisting of similarly numbered operations, and eachsubclass is associated with a character on the corresponding card. Thesecharacters are `arranged in a column and are spaced similarly nto thespacing of the lines I2 of the support Il.

Thus card I3a represents a class consisting of 100 12-operation parts,and the numerals in the column represent the subclasses consisting of100 rst operations, 100 second operations, etc. to be performed on theseparts, the top numeral 100 representing the first operation to beperformed on these parts, the second numeral 100 representing the secondoperation to be performed on the same parts, etc., and the fact thatthere are twelve such numerals indicating that each part of the class isto have twelve operations performed upon it. The 100 pieces making upthis class may be all duplicates, they may be all different, or they maybe partly duplicates and partly otherwise. Also the twelve operations tobe performed on any given piece may be the same or similar to thoseperformed on another piece,l

or they may be dierent partly or Wholly. However, the class of eachpiece as a 12-operation piece is identified by the fact that the cardcarries twelve numerals and the subclass of the piece at a given pointin the processing thereof is identifled by the fact that it is thenundergoing a particular operation, the fifth operation, for example,indicated by the fifth numeral on the card.

Similarly, card I3b represents the class consisting of the 60ll-operation parts, which class is made up of subclasses consisting of60`-first operations, 60 second operations, etc.

Cards I3c to i3m inclusive likewise represent other classes of work inwhich there are a gradually decreasing number of subclasses, the totalrepresented by all cards comprising the complete lot. The order of thecards in their arrangement upon the board need not necessarily followthat illustrated in Fig. 1 however.

'Ihe required dates or time intervals, in this case June 1st to July27th inclusive, are indicated'in column 24 marked Date, two working daysbeing allotted to each space between the lines, in accordance withassumption (b).V The man-hours of plant capacity which are available onthose dates are entered in column marke -Hrs. available."

The cards are then temporarily fastened on the support in any desiredvertical relationship between the areas representing the `starting andfinishing dates, so that the figures fall within the horizontal areasbetween the lines l2. 'I'he figures lying in each area are then totalledin column 26, multiplied by 1.5, and entered in col- 'umn 21 and dividedby 2 in order to convert to Such a satisfactory arrangement is shown inFig. -1. It will be seen that the work to be done on each of the workingdays within the specified interval ls identifiable as to the kinds ofparts to be worked on and the operations which are to be performed onthose parts. For example, on June 15th and 16th the work consists of allsixth operations on 12-operation parts, all flrst operations onll-operation parts, all fourth operations on l0operation parts, and allthird operations on 9-operation parts. corresponding to thev arrangementof cards in Fig. 1 is shown graphically in Fig. 4. It will be seen thatthis distribution satisfies the requirements of assumptions (d), (e),(j), and (g).

By way of contrast, I have shown in Fig. 5 the distributionwhich wouldresult if work on each part were delayed until only enough days remainedin which to finish that part, that is, if all the parts of Fig. 1 wereplaced with their last operations falling on July 26th and 27th. It isobvious that this arrangement does not satisfy the requirements ofassumptions (d) and (f), and that it does not make eiiicient use of theavailable plant capacity. Other rules may be followed to arrive at otherarrangements, but no such other rule has been found to fit allconditions properly.

My invention provides means for treating each case individually and yetin a systematic manner so that the most emcient arrangement of work maybe obtained, all conditions considered. Furthermore, reference to thechart by the factory superintendent or by a foreman charged with a givenportion of the work may be had at any time during the period scheduledto ascertain the condition of the work as compared withschedule, inorder that measures may be taken if necessary to bring up to datecertain identified operations which may then be in arrears.

In carrying out the invention it may be desirable at times to sever' oneor more of the cards into two or more parts and to move the severedparts of the card relatively to a greater or lesser extent whileretaining their identity and association with each other.

If desired, suitable numbers or other symbols may be employed in placeof the dates shown in column 24 of Fig. 1, these numbersy or symbolsbeing arranged in some regular order and being associated with suitabletime intervals.

Other variations inthe details of .the invention may be made withoutdeparting from the spirit thereof so long as such variations fallAwithin the scope of the appended claims.

Having thus described my invention, I claim:

1. A device for facilitating the scheduling 'of work operations throughtrial and error procedure in order to distribute the operations enteringinto a job of work to good advantage over a period of time during whichother jobs are being performed, comprising a support member bearing onits surface a series of elongated appropriately designated spaces ofuniform width, indiciav constituting a time scale registered with saidspaces, a plurality of strips each adapted to relate to a given class ofwork and movably mounted on said support in selected positions at rightangles to said spaces, eachstrip bearing a series of numbers spacedapart the width of said spaces, the combined numbers on a strip beingadapted to represent a given quantity of work to be performed and thearrangement of the numbers on the strip being adapted to indicate theThe distribution of work order of performance of the differentoperations, the strips being adapted to be moved individually andselectively longitudinally a distance corresponding to the width of oneor more of said horizontal spaces in order to adjust the total workrepresented by the rows of numbers on said strips to desired amountsapproximating the available capacity for each division of the timescale.

2. A device for facilitating the scheduling of work operations throughtrial and error procedure in order to distribute the operations enteringinto a job of Work to good advantage over a period of time during whichother jobs are being performed, comprising a support member bearing onits surface a series of elongated appropriately designated spaces ofuniform wid-th, indicia constituting a time scale registered with saidspaces, a plurality of strips each adapted to relate to a given class ofwork and each bearing a series of identical numbers spaced apart adistance corresponding to the width of said spaces, said strips beingmovably mounted on said support in selected positions at right angles`to said spaces, the individual numbers on a strip being adapted toindicate the order of performance of different Work operations and thecombined numbers being adapted to represent a given quantity of Work tobe performed, the numeral bearing portions of the different strips beingof different lengths, the strips being adapted to be moved individuallyand selectively longitudinally a distance corresponding to the width ofone or more of said spaces inforder to adjust the total work representedby the rows of numbers on said strips to desired amounts approximatingthe available work capacity for each division of the time scale.

3. A device for facilitating the scheduling of Work operations throughtrial and error procedure in order to distribute the operations enteringinto a job of Work to good advantage over a period of time during whichother jobs are being performed, comprising a support member bearing onits surface a series of elongated appropriately designated spaces ofuniform width, indicia constituting a time scale registered with saidspaces, a plurality of strips movably mounted on said support inselected positions at right angles to said spaces, each strip beingadapted to relate to a given class of work and bearing a series ofnumbers spaced apart a distance corresponding to the Width of saidspaces, the combined numbers on -a-strip being adapted to represent agiven quantity of work to be performed and the arrangement of thenumbers on the strip being adapted to indicate the order of performanceof the different operations, and a column on said sup-port parallel tothe date scale bearing numbers adapted to indicate the available workcapacity for each division of lthe time scale, said strips being adaptedto be moved individually and selectively longitudinally a distancecorresponding tothe Width 'of one or more of said spaces in order toadjust the total work represented by the rows of numbers on said stripsto the available Work capacity for each division of the time scale.

4. A device for facilitating the scheduling of work operations through4trial and error procedure in order to distribute the operationsentering into la job of work to good advantage over a period of timeduring which other jobs are being performed, comprising a support memberbearing on its surface a series of elongated appropriately designatedspaces of uniform width, indicia constituting a time scale registeredwith said spaces, a plurality of vertical strips each adapted to rel-ateto a given class of Work and each bearing a series of identical numbersspaced apart a distance corresponding to the width of said spaces, saidstrips being movably mounted on said support in selected positions atright angles to said spaces, the individual numbers on a strip beingadapted to indicate the order of performance of different workoperations and the combined numbers being adapted to represent a givenquantity of Work to be performed, the numeral bearing portions of thedifferent strips being of dierent lengths, and a column on said supportparallel to the date scale bearing numbers adapted to indicate theavailable work capacity for each division of the time scale, said stripsbeing adapted to be moved individually and selectively longitudinally a,distance corresponding to the width of one or more of said spaces inorder to adjust the total work represented by the rows of numbers onsaid strips to the available work capacity for each division ot the timescale.

RAYMOND C. HANFORD.

